I'm ready to pour a floor in my new shop, had considered putting in floor heat in, but have decided to go with radiant tube heaters instead. Would you guys still put insulation under the floor or just a vapour barrier?

I guess my deliema is the barn is 48'X 80', I was only going to concrete half of it and use the other half for storage, because of the extra cost of the 2" insulation. If I don't use the insulation I may pour the whole floor, even if I only use 40' of it for a shop a full concrete floor would sure be nice. 

Thanks Brian